This invention relates to a shackling device having a threaded pin and a U-shaped member. More particularly the invention concerns a shackling device having a pin and U-shaped member which cannot become detached from one another.
Shackling devices are used to connect two parts which terminate in rings or the like. For this purpose, shackling devices are arranged so that the two pieces to be joined can be assembled or disassembled at will. Such devices have a great many areas of application, one of the most important being the anchoring of ships.
A traditional shackling device is composed of a U-shaped (stirrup-like) member whose ends are provided respectively with a smooth aperture and an aperture having internal threads, these apertures being coaxial and by a pin which is provided with an elongated smooth portion at one end, extended in the form of an eye, and at the other end by a threaded portion having a diameter corresponding to that of the threaded aperture in the U-shaped member. In order to close the shackling device, it is sufficient to run legs of the U-shaped member through the two rings or the like to be joined and then to close the U-shaped member by the pin, the latter being held in place by screwing. In order to separate the two parts, it is suffice to proceed in reverse order, in other words, to unscrew the pin from the U-shaped member in order to open the shackling device.
The principal disadvantage of traditional shackling devices is that the whole pin, including the threaded portion, can pass through the unthreaded aperture in the U-shaped member. Consequently, it often happens that after the pin has been unscrewed, it suddenly falls out of the U-shaped member if the user is not careful. Obviously, when the pin falls out of the U-shaped member, it can be lost, and the user is left with only the U-shaped member, which is useless by itself as a shackling device. Likewise, there are shackling devices in which the diameter of the threaded portion of the pin is greater than the diameter of the smooth portion thereof. In this case, the two ends of the U-shaped member are provided with identical threaded apertures which can cooperate with two shaped apart threaded portions of the pin. Consequently, when the shackling device is in the closed position, after it has been initially unscrewed, the pin remains connected to the U-shaped member; it is only after being unscrewed further that the pin and U-shaped member can be separated from one another.
A solution of this kind has the disadvantage of being expensive to manufacture, because threaded apertures have to be provided in both ends of the U-shaped member. Moreover, it is unsatisfactory in practice since, after the initial unscrewing has been accomplished, the pin partially blocks the opening of the U-shaped member, thus causing problems in handling it.